Electric railway.



PATENTED MAY 10, 1904.

T. MAHONEY.

ELECTRIC RAILWAY.

APPLIOATION FILED JULY 1. 1903.

N0 MODEL.

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UNITED STATES Patented May 10, 1904.

PATENT OFFICE.

ELECTRIC RAILWAY.

SPECIFICATION forming part of Letters Patent No. 759,453, dated May10,1904. Application filed July 1, 1903. Serial No. 163,863. (No model.)

To (LZZ whom it may concern.-

Be it known that I, TIMOTHY MAHONEY, a citizen of the United States,residing in the city and county of San Francisco, State of California,have invented an Improvement in Electric Railways; and I hereby declarethe following to be a full, clear, and exact description of the same.

My invention relates to improvements in electric-railway systems of thethird-rail type.

Heretofore it has been common in third rail systems to employ a mainfeed-wire and to connect this wire at intervals with the sectional thirdor trolley rail, using suitable switch mechanism operatable by themoving car to cut in or out the current to a section of thetrolley-rail, the current passing from the latter through the car, andthence down to the car-rails to complete the circuit. The chiefobjection to all these systems has been the danger of the third railremaining alive after the car has passed and of some one stepping on thepositive third rail and on one of the negative car-rails at the sametime. Other objections are the necessity and expense of bonding thetrack-rails and the loss of power through leakage or short-circuiting ofthe current between the third rail and its nearby return-conductor, thetrack-rail.

The object of my invention is to do away entirely with a separatefeed-wire and to obviate the necessity of using the car-tracks asreturn-conductors by connecting the two ends of the third rail direct tothe dynamo and providing means for shunting the current from the thirdrail through the car and back to the third rail again.

Having reference to the accompanying drawings, Figure 1 is alongitudinal central section of car-truck and track with diagrammaticwiring. Fig. 2 is a plan view of track and connections. Fig. 3 is alongitudinal central section of switch-box. Fig. 4 is a transversecentral section of same.

A A represent the tracks of an ordinary street-railway, and 2 is anintermediate and parallel surface third rail whose sections areinsulated one from another. The sections are adapted to be normallyconnected electrically in series by means of suitable switches'disposedrelative to the adjacentends of the sections. These switches eachcomprise a box 3, of insulating material, in the bottom of which are twoseparated insulated copper plates 4, and a soft-iron plate 5, normallyresting by gravity on the two plates 4 and bridging the space betweenthem. The adjacent surfaces of the plates 4 5 are adapted to have aclose surface-contact of considerable area. Preferably thearmature-plate 5 has a copper facing 5 on its under side which serves asa conductor of least resistance between plates 4 when the switch isclosed, and

one of plates 4 is connected electrically with one section of rail 2, asindicated by the positive sign The other plate 4 is connected with thesucceeding section, as indicated by the negative sign Thus when armature5 rests on plates4 the circuit between any two adjacent third-railsections is closed, and as the third rail is practically continuous thecurrent from the dynamo or other source of electrical energy, 6, maypass out over one leg of the loop formed by the third rail and returnover the other leg. The box is hermetically sealed by the insulatedcover 7,

which latter also forms the separation between two adjacent sections ofthe third rail.

The car B, which is adapted to travel over the tracks A, carries thetrolley shoes 8, which are in constant contact with the third rail. Oneof these shoes is placed at each end of the car.

Disposed between the car-trucks and supported thereon parallel with thecar axis is a bar 9, having a plurality of soft-iron projections 10,extending downward close to the ground and immediately above the line ofswitch-plates 5. The core projections 10 are wound to formelectromagnets, the adjacent magnets being so wound as to be of oppositepolarity. This line of magnets is designed to present a magnetic surfacesubstantially equal in length to the distance between the trucks,whereby the period is prolonged in which the magnets may act to lift anarmature 5 and cut the current through the car. The magnets 10 are in ashunt-circuit between the two trolley-shoes 8, and as these shoes alwaysstraddle the adjoining ends of two or more sections of rail 2 themagnets are in a constant state of excitation whether the car is movingor standing still.

The main circuit through the car to the controller 11 is indicated at12. The motor is represented at 13. One pole of the motor is connectedwith the controller by a conductor 14 and the other pole with theforward trolleyshoe by the negative wire 15.

The length of the several sections of the third rail is preferably lessthan the length of the line of magnets, since it is desired that themagnets should always be over a switch to lift an armature and so breakthe circuit through the third rail and cause it to pass through the carbefore returning to the third rail. The moment the car has passed aswitch the arma ture falls to complete the circuit through that portionof the third rail lately traversed by the car. Hence in operation atwhatever point along the line of track the car may be the armaturedirectly beneath the car is lifted, thus breaking the circuit throughthe third rail at that point and shunting the current through the car toactuate the motor. From the motor the return-circuit to the dynamo iscompleted through the portion of the third rail in advance of the carand not through the car-tracks or other separate conductor.

In this invention that portion of the third rail on one side of the caris positive, that on the other is negative. It is impossible for one tostep on both the positive and negative portions of the third-rail atonce and get a shock even where the going and return sections of thethird-rail conductor may be on the same street. Moreover, the fartherthese portions are apart the less loss is there from leakage across theintervening space.

The advantages of this system are, first, its safety; second, theelimination of an independent feed-wire and the doing away with allbonding of the car-rails, thereby resulting in a considerable saving incost of construction, and, third, the saving of power effected, sincethere is no return-conductor close by the third rail for the latter toshort-circuit with.

Having thus described my invention, what I claim, and desire to secureby Letters Patent,

1. The combination with a car or like movable body, of a sectionalconductor comprising alined separated sections, of removableswitch-boxes interposed between and in the line of the sections, contactmembers in each of said boxes, one of said members connectedelectrically with one adjacent section and the I other member with theother adjacent section, an armature-plate normally resting by gravity onsaid contacts, and a plurality of connected alined magnets on the car inthe plane of said armatures, alternate magnets being of oppositepolarity t0 the intermediate magnets.

2. In an electric-railway system, the combination with a sectionalconductor and switches normally connecting the sections of saidconductor, of a plurality of alined connected cooperating magnetscarried by the car, said line being substantially equal to the distancebetween the switches, and said magnets being wound so that alternatemagnets are of opposite polarity t0 the intermediate magnets whereby aline of magnetic attraction of practically uniform strength throughoutits length is produced.

In witness whereof I have hereunto setmy hand.

TIMOTHY MAHONEY. Witnesses:

OLIVER DIBBLE, G. M. D. Teens.

